A different approach for considering the effect of non-proportional loading path on the forming limit diagram of AA5083

2013 ◽  
Vol 50 ◽  
pp. 165-173 ◽  
Author(s):  
F. Zhalehfar ◽  
S.J. Hosseinipour ◽  
S. Nourouzi ◽  
A.H. Gorji
Keyword(s):  
Forming Limit Diagram ◽  
Loading Path ◽  
Forming Limit ◽  
Proportional Loading

Loading Path Dependence of Forming Limit Diagram of a TRIP800 Steel

2011 ◽  
Vol 4 (1) ◽  
pp. 75-83 ◽  
Author(s):  
Kyoo Sil Choi ◽  
Ayoub Soulami ◽  
Wenning Liu ◽  
Xin Sun ◽  
Moe Khaleel
Keyword(s):  
Path Dependence ◽  
Forming Limit Diagram ◽  
Loading Path ◽  
Forming Limit

scholarly journals Viscous Backpressure Forming And Feasibility Study of Hemispherical Aluminum Alloy Parts

2021 ◽  
Author(s):  
Tiejun Gao ◽  
Jiabin Zhang ◽  
Kaixuan Wang
Keyword(s):  
Finite Element Analysis ◽  
Aluminum Alloy ◽  
Forming Limit Diagram ◽  
Loading Path ◽  
Forming Limit ◽  
Distribution Law ◽  
Forming Process ◽  
Element Analysis ◽  
Technical Feasibility ◽  
Forming Limit Diagrams

Abstract Hemispherical aluminum alloy parts are extensively used in modern aerospace and other manufacturing fields. However, wrinkling and cracking easily occur due to the large deformation of the parts, which leads to a complicated forming process. This research proposes a viscous backpressure forming method for hemispherical aluminum alloy parts. The forming limit diagram of LF2 sheet is established through the forming limit experiments. By the combination of finite element analysis and experimental verification, the forming process of the parts under different viscous backpressure and loading path conditions as well as the distribution law of stress-strain and wall thickness of the parts, are obtained. By comparing with the forming limit diagrams, technical feasibility of this forming process is discussed. The research results show that qualified parts can be formed using the viscous backpressure forming method under the conditions of viscous backpressure loading throughout the process with the backpressure at or above 12MPa. This provides a reference for the backpressure forming of hemispherical aluminum alloy parts.

An Investigation Into the Prediction of Forming Limit Diagrams for Normal Anisotropic Material Based on Bifurcation Analysis

2011 ◽  
Vol 78 (3) ◽  
Author(s):  
A. Jaamialahmadi ◽  
M. Kadkhodayan
Keyword(s):  
Bifurcation Analysis ◽  
Work Hardening ◽  
Yield Criterion ◽  
Forming Limit Diagram ◽  
Optimization Method ◽  
Forming Limit ◽  
Proportional Loading ◽  
Normal Anisotropy ◽  
Left Hand ◽  
Prediction Limit

In this paper, formula derivation for bifurcation analysis based on a constitutive model including Hill 48 yield criterion with normal anisotropy of a pointed vertex on subsequent yield loci to predict the entire forming limit diagram (FLD) is carried out. Proportional loading, total deformation theory of plasticity, and power law relation are assumed. Predicted limit strains for Hill’s zero and minimum extension of localized neck orientation is derived. The dominancy of zero extension and minimum extension on the left-hand side of FLDs for different work hardening components and r-values are investigated in detail. An implicit four order rational function equation for major strain, which preferred that the orientation of neck correspond to minimum value of limit strain, is found by a developed optimization method. Optimized predicted limit strains for typical work hardening components and different r-values are obtained and discussed. Limit strains vary directly on the left and reversely on the right-hand side of FLD when r-value increases. Comparison between the predicted and experimental results exhibits a better agreement compared with those from the isotropic material. In addition, on the left-hand side, the resulted prediction limit strains represent a full dependency to assumed yield criterion. A comparison between the current work and Chow et al. results are performed and discussed in detail.

Forming Limit of Sheet Metal Based on Different Property Imperfection

2010 ◽  
Vol 146-147 ◽  
pp. 1206-1210
Author(s):  
Yu Yan ◽  
Hai Bo Wang
Keyword(s):  
Uniaxial Tension ◽  
Sheet Metal ◽  
Yield Criterion ◽  
Tension Test ◽  
Loading Path ◽  
Forming Limit ◽  
Proportional Loading ◽  
Material Parameters ◽  
Instability Theory ◽  
Similarities And Differences

From more than one uniaxial tension test curve, it can be found that mechanics property of sheet metal is inhomogeneous. Based on this truth, a new method for prediction of forming limit of sheet metal is proposed. Using this method, theoretical FLDs are obtained under proportional loading path based on Hill48 yield criterion. The effects of several material parameters on forming limit are obtained. Similarities and differences between this method and M-K instability theory are analyzed and some advices on the application of this method are given.

Prediction of the forming limit diagram on the basis of the damage criterion under non-proportional loading

2001 ◽  
Vol 215 (4) ◽  
pp. 405-414 ◽  
Author(s):  
C L Chow ◽  
X-J Yang
Keyword(s):  
Damage Mechanics ◽  
Evolution Equations ◽  
Damage Model ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Proportional Loading ◽  
Damage Criterion ◽  
Arbitrary Loading ◽  
Anisotropic Plastic ◽  
Theory Of Damage

Based on the theory of damage mechanics, a recently developed anisotropic plastic damage model for the prediction of forming limit diagrams (FLDs) is extended to take into account the effect of rotation of the principal damage coordinates on the deformation and damage behaviour. With the aid of the damage plastic potential, the damage evolution equations are established. A damage criterion for localized necking under arbitrary loading history is proposed. The model is employed to predict the FLDs of AL6111-T4 alloy. The predicted results agree well with those determined experimentally.

Studies on Formability Behaviour of Aluminium Alloy Sheets with Ceramic Nanocoatings

2014 ◽  
Vol 984-985 ◽  
pp. 482-487
Author(s):  
M. Jinnah Sheik Mohamed ◽  
N. Selvakumar
Keyword(s):  
Tensile Force ◽  
Rolling Direction ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Proportional Loading ◽  
Trouble Shooting ◽  
Out Of Plane ◽  
Safe Region ◽  
Strain Paths ◽  
Experimental Works

Forming limit diagram presents limit strains for different linear strain paths. In other words it indicates localized formability of sheet metals under different proportional loading and is considered a powerful tool for trouble shooting in sheet-metal forming industries. In this study in-plane and out-of-plane forming limit diagrams were determined for aluminum 5052. In the experimental works, all specimens were prepared in the rolling direction and annealed before testing. Forming up to fracture was carried out on INSTRON UTM with a tensile force of 1N. The sheet samples were subjected to tension-compression state of strain by varying the notch sizes of the samples. FLD was drawn by plotting the minor strain in abscissa and corresponding major strain in ordinate and by drawing a curve which separates the safe region from the unsafe region.

Optimization of Tube Hydroforming Process Using Probabilistic Constraints on Failure Modes

2011 ◽  
Vol 62 ◽  
pp. 21-35 ◽  
Author(s):  
Anis Ben Abdessalem ◽  
A. El Hami
Keyword(s):  
Failure Modes ◽  
High Reliability ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Forming Limit Diagram ◽  
Plastic Instability ◽  
Probabilistic Constraints ◽  
Forming Limit ◽  
Reliability Based Design ◽  
Hydroforming Process

In metal forming processes, different parameters (Material constants, geometric dimensions, loads …) exhibits unavoidable scatter that lead the process unreliable and unstable. In this paper, we interest particularly in tube hydroforming process (THP). This process consists to apply an inner pressure combined to an axial displacement to manufacture the part. During the manufacturing phase, inappropriate choice of the loading paths can lead to failure. Deterministic approaches are unable to optimize the process with taking into account to the uncertainty. In this work, we introduce the Reliability-Based Design Optimization (RBDO) to optimize the process under probabilistic considerations to ensure a high reliability level and stability during the manufacturing phase and avoid the occurrence of such plastic instability. Taking account of the uncertainty offer to the process a high stability associated with a low probability of failure. The definition of the objective function and the probabilistic constraints takes advantages from the Forming Limit Diagram (FLD) and the Forming Limit Stress Diagram (FLSD) used as a failure criterion to detect the occurrence of wrinkling, severe thinning, and necking. A THP is then introduced as an example to illustrate the proposed approach. The results show the robustness and efficiency of RBDO to improve thickness distribution and minimize the risk of potential failure modes.

Formability Analysis of AA6061 Sheet in T6 Condition

2015 ◽  
Vol 766-767 ◽  
pp. 416-421
Author(s):  
S. Vijayananth ◽  
V. Jayaseelan ◽  
G. Shivasubbramanian
Keyword(s):  
Experimental Method ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Ansys Software ◽  
Limit Curve ◽  
High Corrosion Resistance ◽  
Forming Limit Curve ◽  
Drawing Test ◽  
Deep Drawing Test ◽  
Alloy 6061

Formability of a material is defined as its ability to deform into desired shape without being fracture. There will always be a need for formability tests, a larger number of tests have been used in an effort to measure the formability of sheet materials. Aluminium Alloy 6061 is a magnesium and silicon alloy of aluminium. It is also called as marine material as it has high corrosion resistance to seawater. In this paper Formability test of AA6061 sheet is done by Forming Limit Diagram (FLD) Analysis. FLD or Forming Limit Curve (FLC) for the forming processes of AA6061 sheets is obtained by Experimental method and FEM. Experimental method involves Deep drawing test of the sheet and ANSYS software is used for FEM.

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